<template>
  <div class="upload-cover" @click="showCoverSelect">
    <div class="cover-wrap">
      <!-- <img class="cover-image" ref="cover-image" :src="coverImage"> -->
      <img class="cover-image" ref="cover-image" :src="value">
    </div>
    <el-dialog title="选择封面" :visible.sync="dialogVisible" append-to-body>
      <el-tabs v-model="activeName" type="card">
        <el-tab-pane label="素材库" name="first">
          <!-- 
            ref有两个作用
            1.作用到普通html标签上可以获取DOM 
            2.作用到组件上可以获取组件
          -->
          <image-list :is-show-add="false" :is-show-action="false" :is-show-selected="true" ref="image-list">
          </image-list>
        </el-tab-pane>
        <el-tab-pane label="上传图片" name="second">
          <input type="file" ref="file" @change="onFileChange">
          <img ref="preview-image" width="100px">
        </el-tab-pane>
      </el-tabs>
      <span slot="footer" class="dialog-footer">
        <el-button @click="dialogVisible = false">取 消</el-button>
        <el-button type="primary" @click="onCoverConfirm">确 定</el-button>
      </span>
    </el-dialog>
  </div>
</template>

<script>
  import {
    uploadImage
  } from '@/api/image';
  import ImageList from '@/views/image/components/image-list';
  export default {
    // 组件名称
    name: 'UploadCover',
    // 组件参数 接收来自父组件的数据
    // props: ['cover-image'],
    props: ['value'],
    // 局部注册的组件
    components: {
      ImageList
    },
    // 组件状态值
    data() {
      return {
        dialogVisible: false,
        activeName: 'second'
      }
    },
    // 计算属性
    computed: {},
    // 侦听器
    watch: {},
    created() {},
    mounted() {},
    // 组件方法
    methods: {
      showCoverSelect() {
        // 展示选择封面的弹窗
        this.dialogVisible = true
      },
      onFileChange() {
        //获取文件对象
        const file = this.$refs.file.files[0]
        //图片预览
        const blob = window.URL.createObjectURL(file)
        this.$refs['preview-image'].src = blob
        //防止用户选择同一个文件不处罚 change 事件
        // this.$refs.value = ''
      },
      onCoverConfirm() {
        //如果是 上传图片 ，并且input-file有选择的文件，才执行上传图片操作
        if (this.activeName === 'second') {
          const file = this.$refs.file.files[0]
          if (!file) {
            this.$message('请选择图片')
            return
          }
          //执行上传文件操作
          const fd = new FormData()
          fd.append('image', file)
          uploadImage(fd).then((res) => {
            console.log(res);
            //关闭弹出层
            this.dialogVisible = false
            //展示上传的图片
            this.$refs['cover-image'].src = res.data.data.url
            //通知将图片地址发送给父组件
            // this.$emit('update-cover', res.data.data.url)
            this.$emit('input', res.data.data.url)
          }).catch((err) => {

          });
        } else if (this.activeName === 'first') {
          //还有一种组件通信方式：父组件可以直接访问子组件数据
          const imageList = this.$refs['image-list']
          const selected = imageList.selected
          if (selected === null) {
            this.$message('请选择封面图片')
            return
          }
          //关闭对话框
          this.dialogVisible = false
          //修改父组件绑定数据
          this.$emit('input', imageList.images[selected].url)
        }
      }
    },
  }

</script>

<style scoped lang='less'>
  .cover-wrap {
    width: 150px;
    height: 120px;
    border: 1px solid #000;

    .cover-image {
      height: 120px;
      min-width: 100%;
    }
  }

</style>
